Description

The LRIS2K is a contactless memory powered by the received carrier electromagnetic wave. It is a 2048-bit electrically erasable programmable memory (EEPROM). The memory is organized as 64 blocks of 32 bits. The LRIS2K is accessed via the 13.56 MHz carrier electromagnetic wave on which incoming data are demodulated from the received signal amplitude modulation (ASK: amplitude shift keying). The received ASK wave is 10% or 100% modulated with a data rate of 1.6 Kbit/s using the 1/256 pulse coding mode or a Data rate of 26 Kbit/s using the 1/4 pulse coding mode. Outgoing data are generated by the LRIS2K load variation using Manchester coding with one or two subcarrier frequencies at 423 KHz and 484 kHz. Data are transferred from the LRIS2K at 6.6 Kbit/s in low data rate mode and 26 Kbit/s high data rate mode. The LRIS2K supports the 53 Kbit/s in high data rate mode in one subcarrier frequency at 423 kHz. The LRIS2K follows the ISO 15693 recommendation for radio frequency power and signal interface.

Memory mapping

The LRIS2K is divided into 64 blocks of 32 bits as shown in Table 2. Each block can be individually read- and/or write-protected using a specific lock or password command. The user area consists of blocks that are always accessible. Read and Write operations are possible if the addressed block is not protected. During a Write, the 32 bits of the block are replaced by the new 32-bit value. The LRIS2K also has a 64-bit block that is used to store the 64-bit unique identifier (UID). The UID is compliant with the ISO 15963 description, and its value is used during the anticollision sequence (Inventory). This block is not accessible by the user and its value is written by ST on the production line. The LRIS2K also includes an AFI register in which the application family identifier is stored, and a DSFID register in which the data storage family identifier used in the anticollision algorithm is stored. The LRIS2K has four additional 32-bit blocks in which the Kill code and the password codes are stored.

The LRIS2K supports the following commands:
● Inventory, used to perform the anticollision sequence.
● Stay Quiet, used to put the LRIS2K in quiet mode, where it does not respond to any inventory command.
● Select, used to select the LRIS2K. After this command, the LRIS2K processes all Read/Write commands with Select_flag set.
● Reset To Ready, used to put the LRIS2K in the ready state.
● Read Block, used to output the 32 bits of the selected block and its locking status.
● Write Block, used to write the 32-bit value in the selected block, provided that it is not locked.
● Lock Block, used to lock the selected block. After this command, the block cannot be modified.
● Write AFI, used to write the 8-bit value in the AFI register.
● Lock AFI, used to lock the AFI register.
● Write DSFID, used to write the 8-bit value in the DSFID register.
● Lock DSFID, used to lock the DSFID register.
● Get System Info, used to provide the system information value
● Get Multiple Block Security Status, used to send the security status of the selected block.
● Initiate, used to trigger the tag response to the Inventory Initiated sequence.
● Inventory Initiated, used to perform the anticollision sequence triggered by the Initiate command.
● Kill, used to definitively deactivate the tag.
● Write Password, used to write the 32 bits of the selected password.
● Lock Password, used to write the Protect Status bits of the selected block.
● Present Password, enables the user to present a password to unprotect the user blocks linked to this password.
● Fast Initiate, used to trigger the tag response to the Inventory Initiated sequence.
● Fast Inventory Initiated, used to perform the anticollision sequence triggered by the Initiate command.
● Fast Read Single Block, used to output the 32 bits of the selected block and its locking status.